Breaker points

[bozza_boatie]

Hi, I am setting breaker points on a 1985 4hp Johnson,
I have a service manual which states a 0.020 inch gap. I just need to know is this gap set between the "top" part of the camshaft (the disk that connects to the cranshaft) and the breaker arm.
If this is correct the breaker arm will never touch the camshaft, is this correct?
The reason i ask is it doesnt seem right cause the breaker arm will never move and no ignition. How does this work then?


Please help cause Im really confused

Thanks

 

[JB]

Re: Breaker points

The .020" gap you want to set is between the two contacts of the points when the cam follower is on the peak of the cam, Bozza. Same for each set of points.

As the crank rotates the cam will then open the contacts .020" to fire each cylinder.

Good luck.

 

[imported_MattG]

Re: Breaker points

If you are more of a picture person like I am.

You want to insert the feeler gauge like so. Of corse the gap would be that big lol.

When inserting the feeler gauge I make sure its slides through real nice, what you dont want is when you insert the gauge that it moves the arm.

My pants lol

 

[bozza_boatie]

Re: Breaker points

Okay thanks guys I get it now, I thought something didnt seem right.

 

[kenmyfam]

Re: Breaker points

Are you re-gapping or fitting new points ??
If you are re-gapping then you should inspect the contact surfaces carefully, you may find that one side has a build up and the other side a slight hollow at the contact point. If this is the scenario then you should make the surfaces flat again with a light stone. Then if you are stoning them you have to be careful not to go too far as the surfaces are usually just "case hardened" and if you go too deep your motor will not run well for long and you will find a much bigger build up and "hole" on the contact surfaces.
Far better to fit new ones and keep the old ones as emergency spares.
I learned this the hard way when I was about 100 miles from home with a motorcycle, pouring with rain and had to re dress the surfaces 4 times on my way home with my limited toolkit.